Defence minister Dimitar Stoyanov spoke by phone today with Romanian deputy prime minister and defence minister Radu Miruta and Turkish defence minister Yasar Guler. They discussed security in the Black Sea after overnight strikes on two merchant ships, the ministry's press office said.

This story follows our earlier report on president Iliana Iotova cancelling her visit to Veliko Tarnovo after drones hit two ships in Bulgaria's exclusive economic zone in the Black Sea.

Three aerial drones hit one ship 18 nautical miles east of Byala. The other ship sank after a strike 17 nautical miles east of Krapets.

Attacks on merchant ships in the Black Sea are a gross breach of international maritime law, and the Bulgarian government condemns them, Stoyanov said. He called on Bulgaria, Romania and Turkey to step up surveillance and share intelligence with each other and with NATO structures.

The situation in the Black Sea is getting more complex, and allies must step up their joint action, the minister said. In his view, the growing risks can only be met with effective information sharing, closer surveillance and tight coordination.

"Keeping the region's waters safe and open to shipping is in everyone's interest and is our shared responsibility," Stoyanov said.

Prime minister Rumen Radev announced new drone attacks on ships in the Black Sea this morning and called them completely unacceptable. He spoke by phone with European Commission president Ursula von der Leyen and NATO secretary general Mark Rutte. Radev called on both for joint efforts to stop the attacks, the Council of Ministers' press office said.

Updated (13.10, 16:46): Interior ministry chief secretary Lyubomir Nikolov said it cannot be said for certain whether the second ship has sunk, as was first reported. The first ship was most likely hit by three drones about 15 miles east of Byala, not 18 miles. The 15 rescued sailors, eight Azerbaijanis and seven Ukrainians, are in St Anna hospital and the Naval Hospital in Varna. Five sailors from Syria and Egypt were rescued from the second ship. An emergency meeting of the Security Council at the Council of Ministers has been called. Nikolov said a proposal has been made to equip Bulgaria's Black Sea border with anti-drone systems.